Air separation devices



May 17, 1960 R. HALLWORTH AIR SEPARATION DEVICES Filed Feb. 3. 1958 P2,936,885 C Patented May 17, 1960 Am SEPARATION DEVICES RobertHallworth, Cheadle, England, assignor to Henry Simon Limited, Stockport,Cheshire, England, a British company I Application February a, 1958,Serial or-112,860 :J. I

Claims priority, application Great Britain February 11, 1957 Claims; or.209436) purities by aspiration; While such special separators aresuitable in circumstances where the volume'of elevating air is large andthe quantity of material elevated is comparatively small they are'ata.conside'rable.idisadvantage when considered in relation to a highcapacity,

low air volume pneumatic conveying system in that, be-

cause even if the wholeof the elevating air is redirected for thepurpose, the total volume ofair, available for aspiration is sufficientonly to provide aspirating velocities in channelsof comparatively smalleross-section.- The effect of the free admission to such a channel ofthe comparatively large quantity of materialelevated would be to createa material curtainlayer of such considerable thickness that completeaspiration would-beirnpossible in the space available. Furthermore,with'such a. thick nected to a separator 2 of substantially rectangularcrosssection by a transition element 3 of constant cross-sectional areaarranged to spread the elevated materials over thewhole width of theseparator 2. Immediately above the transition element 3 a branchair-duct'4 is provided whereat the elevating air is separated from thestream of curtain layer of material traversing an aspirating channel,

the separated elevated material .being collected in. a collectingchamber from which it is transferred to a regulating hopper providedwith a plurality of .narrow, preferably adjustable, slots, through whichthe elevated material discharges in a plurality of relatively thincurtain system:comprises am ain elevating pipe whichdischarges into anair separator,

layers in an aspirating channel along which a-controll-able quantity ofseparated elevating air is directed so as to pass successively througheach curtain layer. With such an improved arrangement,eifectiveaspiration is provided while the slots trap and retain withinthe hopper any large impurities which mightdamage the separator outletfeeder. 1 p Y Referring to the accompanying drawings: Figuresl and 2areside and crosssectionalviews respectively of an elevating system inaccordance with the invention, and I I I I I F1gure 3 is a section onBB:of Fig ure 2, a secondary separator allsobeing'indicated.-

1a the embodiment s ow ime u per; terminate or main elevating'pipar'br'eircfiiar'emanated is coni elevated material allowing thelatter to continue to move under its own impetus along a path bounded bya deflector surface 5 which in conjunction with a suitablematerial-cushion check-box 6 re-directs it into a collecting', chamber7, a portion of the base of which takes the form of a counterbalancedhinged trap valve 8 adjustably arranged to permit the free passage of,all material in excess of that quantity required to form a sealing layerof suflicient thickness to prevent the passage of air therethrough.Immediately below the collecting chamber 7 and having its wallscontinuous with the walls thereof, is a regulating hopper 9, one wall 10of which forms part of the boundary of a downward extension 11 of thebranch air-duct while the opposite wall 12, which is inclined inwardlytowards the bottom and is provided with a plurality of adjustable slots13 each of which extends horizontally over the full width of the hopper9, forms part of the boundary of an aspirating channel 14 into which airfrom the extension 11 of the branch airduct is directed. At a positionbelow the regulating hopper 9, the aspirating channel 14 and thedownward extension 11 of the branch air duct conjoin to provide a Y-junction 15, a'lower extension of which forms the outlet duct foraspirated material and communicates with a rotary or similar outletvalve-feeder 16.

The cross-sectional area of the aspiratingchannel 14 may be from 2 to 2/2 times that of the main elevating pipe Land its walls are parallel sothat the wall 17 opposite the inwardly inclined and slotted wall of theregulating hopper is also inclined and provides a receiving surface downwhich aspirated material may'be guided to the outlet valve-feeder 16.Above the top exit, slot of the regulating hopper 9 the narrow sidewalls of the I aspiratingchannel 14 converge to make a junctionwith ahorizontal bye-pass; air-duct 18, which passing along the outside of thecollecting chamber connects the branch air-duct 4 with an outletair-duct 19 leading to a secondary air separator 20, preferably of thecyclone type. At the junction of the aspirating channel 14 and thebyepass air-duct 18, an adjustably hinged proportioning ai rvalve 2-1 isprovided whereby the relative quantities of separated elevating airflowing from branch air-duct- 4 through the aspirating duct 14 and thebye-pass"duct-1 8 respectively to outlet air-duct 19 can be regulated sothat only thatproportion of the total separated air in branch air-duct 4which is necessary for a specific aspirating requirement iscaused toflow through the aspirating-duct 14, the unwanted proportion of theseparated air being caused to flow along'the bye-pass air-duct 18 tooutlet air-duct 19 thus bye-passing the aspirating channel, the saidadjustably hinged proportioning air-valve being manually controllable bymeans of an external adjustment knob 30 mounted on an extension of theair-valve spindle 31 which passes through the wall of the duct totheoutside of the apparatus in order to provide that the relativeproportions of separated air flowing along the-alternative pathsavailable can be adjusted to an while the apparatus is in operation. I I

Material which enters the collecting chamber 7 after having beenseparated from the conveying air, forms on the base of the chamber alayer, part of which rests on ..the counter-balanced hinged trap valve8. .When this layer is of such depth and density as to prevent anysubstantial flow of air from the collecting chamber through thevalye .8,the weight of the material supported onfthe valve 8 causes 'it'to openby an amount which will permit optimum the passage therethrou'gh of aquantity of material equal to the amount being continuously received inthe collecting chamber 7. From the collecting chamber 7 the materialfalls by gravity into the regulating hopper 9 wherein a-substantiallyconstant level of material is maintained byadjustment of theslot-openings 13 leading therefrom the said adjustment applyingsimultaneously to the effective depths of all the slots, and beingregulated in accordance with movements of a manually operable adjustmentknob 32 situated on the outside ofone or" the lateral boundary walls ofthe apparatus, and carried on a horizontally extending shaft 33, whichsupports two pinions 34 engaging racks 36 carried at each side of aslotted slideplate 3S. Rotation of knob raises or lowers the plate 35and so enables the setting of the-optimum slot depth to be effectedwhile the apparatus is in operation; The material passes into theaspirating channel 14 through all slots 13-below the top level of thematerial, at a velocity subject to the pressure-head and the angle-ofslip of material, and tends to attain a vertical path under theinfluence of gravity, but, due to the lifting tendencies of theaspirating air flowing upwards in the aspirating channel 14 will bedeflected so that heavier material elements will move towards and downthe remote side 17 of the aspirating channel while the lighter materialelements will be' entrained in the air and transported via the outletair-duct 19 to the secondary air separator 20, the quantities of theseparated elevating air which are caused to pass up the aspiratingchannel and through the bye-pass duct 18 thereof being rela-t tivelycontrolled by the adjustable proportioning air valve associatedtherewith.

The aspirating channel wall 17 which is parallel with the slotted wallis provided with a covered opening 22 to permit of access to the slots13; observations windows 23 are provided in the narrow walls of theaspire-ting channel 14' to facilitate slot and air quantity adjustment,and a service door 24 is provided in the side wall of the regulatinghopper 9 to give cleaning access for'removing trapped materials.

By providing that the material to be aspirated is passed into theaspirating channel 14 through narrow slots 13, it is ensured that largeunwanted material which'could damage the outlet feeder-valve 16 isprevented from entering the aspirating channel14 and also that thematerial which passes through the slots 13 traverses the aspiratin'gchannel 14 in a plurality of thin curtain-layers through which theseparated elevating air can pass freely to effect adequate aspirationfor the removal of'impurities. By enabling' the relative quantities ofair passing alongthe aspirating channel '14 or the alternative byepasschannel-18 to be adjusted by the proportioning-valve means 2 1 it isensured that sensitive control of the intensity of aspiration may beachieved. Since the aspirating channel 14 is arranged to slope theaspirated material passes down one wall of the channel and thus offersthe minimum interference with the aspirating process.

What I claim is: t j

1. An air separation device for use in pneumatic ele'- vating systems,comprising an air separator, a main elevating pipe discharging into saidair separator, a collectin'g'charnber in which separated elevatedmaterial from said'separator iscollected, a regulating hopper into whichsaid separated elevated material is transferred from saidcollectingchar'nbensaid regulating hopper having a plurality of narrowadjustable slots, an aspirating channel running past and incommunication with said slots so that said separated elevated materialdischarges in a plurality of relatively thin curtain layers into saidaspirating channel, and duct means for conveying a controlled quantityof separated elevating air from said separator to said aspiratingchannel enabling-said separated elevating air 'to pass successivelythrough each said curtain layer. 7

'2.An air separation device for use in pneumatic elevating systems,comprising an air separator, a main elevating pipe discharging into saidair separator, a collecting chamber in which separated elevated materialfrom said separator is collected, a regualting hopper into which saidseparated elevated material is transferred from said collecting chamber,said regulating hopper being tapered and having an inwardly inclinedwall having a plurality of narrow adjustable slots therein, anaspirating channel having parallel walla-one ofwhich is common with saidslotted well, said separated elevated material discharging through saidslots in a plurality ofreiatively thin curtain layers into saidaspirating channel, duct means for conveying a controlled quantity ofseparated elevating air fromsaid separator to said aspirating channelenabling said separated elevatingair to pass succes- V sively througheach said curtainilayer, and an outlet valve feeder means below saidaspirating channel, the wall of said aspirating channel opposite saidcommon slotted wall acting as a receiving surface down which saidmaterial whichhas not been removed by aspiration-may be guided-to saidoutlet valve feeder.

3. Annie separation device for use'inpneumatic elevating systems,comprising an air separator, a main elevating pipe discharging into saidair separator, a collecting chamber in which separated elevated materialfrom said separator is collected, a regulating hopper into which saidseparated elevated material is transferred from said collecting chamber,said regulating hopper having a plurality of narrow adjustable slots, anaspirat ing channel'running past'and in communication with'said slots sothat said separated elevated material discharges in a plurality ofrelatively thincurtain layers into said aspirating channel, duct meansfor conveying a controlled quantity of separated elevating air from saidseparator to said aspirating channel enabling said separated elevatingair to pass-successively through each said curtain layer, bye-pass meanswhich bye-passes said aspirating channel, and an adjustable'air valveassociated with said bye-pass means, said air valve controlling therelative proportions of the separated elevating airpassingthrough saidaspirating-channel and said bye-pass means' 4. An air separation devicefor use in pneumatic elevating systems, comprisingan air separator, amain elevating pipe .discharging'into'said air separator, a collectingchamber in Which separated elevated material from said separator iscollected, a regulating hopper into which said separated elevatedmaterial is transferred from said collecting chamber, said regulatinghopper being tapered and having an inwardly inclined-wall havinga-plurality of narrow adjustable slots therein, anaspirating channelhaving parallelwalls', ohe of which is common vw'th-said slotted wall,.said separated elevated material discharging through said slots'in aplurality of relatively thin curtain layers into said aspiIatin-gchannel, vduct means for conveying a controlled quantity of sep'aratedelevating air from said separator to said aspiratingi channel-enablingsaid separated elevating air to'pass successively through each'saidcurtain layer, an outlet valve feeder means below said aspiratingchannel, the wall of said aspirating channel opposite said commonslotted wall acting as a receiving surface down which said materialwhich has not been removed by aspiration may be guided to said outletvalve feeder, and being provided witha covered opening to permitaccess'to said slots, bye-pass means which byepasses said aspirating"channel, and an adjustable air valve associated with said bye-passmeans, said air valve controlling the relative proportions of theseparated elevating air passing through said aspirating channel and saidbye-pass means,observation windows being provided in said aspiratingchannel in the walls adjacent'the slotted wall to facilitate slot andair control adjustment.

5. An air-separation device foruse in pneumatic elevating systemscomprising an air separator, a main elevatingpipe discharging into saidair separator," a collecting chamber in which separated el'evatedrnaterial from said separator is collected,a regulating "hopper intowhich said separated elevated material is transferred from saidcollecting chamber, said regulating hopper being tapered and having aninwardly inclined wall having a plurality of narrow adjustable slotstherein, an aspirating channel having parallel walls, one of which iscommon with said slotted wall, said separated elevated materialdischarging through said slots in a plurality of relatively thin curtainlayers into said aspirating channel, duct means for conveying acontrolled quantity of separated elevating air from said separator tosaid aspirating channel enabling said separated elevating air to passsuccessively through each said curtain layer, an outlet valve feedermeans below said aspirating channel, the wall of said aspirating channelopposite said common slotted Wall acting as a receiving surface downwhich said material which has not been removed by aspiration may beguided to said outlet valve feeder, and being provided with a coveredopening to permit access to said slots, bye-pass means which bye-passessaid aspirating channel, and an adjustable air valve associated Withsaid bye-pass means,

aeaeese said air valve controlling the relative proportions of theseparated elevating air passing through said aspirating channel and saidbye-pass means, observation windows being provided in said aspiratingchannel in the walls adjacent the slotted wall to facilitate slot andair control adjustment, and a service door being provided in the sidewall of the said regulating hopper to give cleaning access for removingmaterials trapped by said slots.

6. An air separation device'for use in pneumatic elevating systems,comprising an air, separator, a mainelevating pipe discharging into saidair separator, 21 collecting cnamber in which separated elevatedmaterial from said separator is collected, a regulating hopper, acounterbalanced hinged trap valve in the bottom of said collectingchamber adjustably arranged to permit the passage to said regulatinghopper of separated elevated material in excess of that quantityrequired to form a sealing,

layer of suflicient thickness to prevent thepassage of air therethrough,said regulating hopper having a plurality of narrow adjustable slots, anaspirating channel running past and in communication with said slots sothat said separated elevated material discharges in a plurality ofrelatively thin curtain layers into said aspirating channel, and ductmeans for conveying a controlled quantity of separated elevating airfrom said separator to said aspirating channel enabling said separatedelevating air to pass successively through each said curtain layer.

References Cited in the file of this .patent UNITED STATES PATENTS GreatBritain Nov. 3, 1937

